Are you tense, irritable and ashamed of your domestic life? Do you wonder whether your children are hideous, your partner lazy and your house a mess? Fear not: like five million people every week you can find real people whose lives, tastes and behaviour can console you by being far, far worse. Rod Williams’s pioneering documentary series for ITV, Neighbours From Hell, and the increasingly deplorable reality TV shows such as Big Brother have mutated into Wife Swap and Life Swap programmes currently taking Britain, Germany and now America by storm. It formula is simple and contrived: take two people from widely contrasting backgrounds and ask them to live in each other’s shoes for a week or two.

Last week, it was the turn of Michael Portillo, who gave one of his increasingly cuddly performances as the leader the Tory party most lacks. The urbane MP for Chelsea & Westminster is childless and, as someone “just reasonably rich” had no idea how to do his own laundry or washing-up. In BBC2’s How Michael Portillo Became a Single Mother, he was asked to live in the shoes of Jenny Miner, a 31-year old single mother of four living in Merseyside. Like Matthew Parris 20 years ago, he soon found that feeding yourself on the minimum wage was very hard indeed, especially with children who long for pasta carbonara, want a karaoke party and won’t go to bed or learn table manners. Despite claims that he had “dominated the washing machine”, it was clear that living the life of the underclass was always going to be an unpleasant shock. “Welcome to the real world, Mikey,” as Jenny, observing him, commented dryly.

Yet what was real for her was probably almost surreal for many viewers, who do not have to cope with such extreme demands on their patience and finances. Increasingly exhausted and flustered, Portillo still managed to exude charm, patience and an endearing willingness to persist. “Private faces in public places/Are wiser and nicer/Than public faces in private places,” WH Auden observed, but for once this adage proved wrong. Portillo’s public face managed surprisingly well in a private place, where his fame was barely recognised. He bonded with Jenny’s eldest daughter but found her sons just manageable and her 8-year-old Elouise, impossible; not being able to cuddle or punish, as a real parent would do, the cameras kept the balance of power between adult and child instead. All of this was highly enjoyable, but those who relish seeing the difficulty of others in dealing with domestic difficulties were probably more impressed that Jenny not only held down two jobs, kept her house spotless but got one son to do trumpet practice and played Scrabble with her kids. Just as Jenny commented gently on where her substitute was going wrong, so the programme invited us to question our own assumptions about single-mothers and child-care.

All of us, parents or not, are fascinated by the details of other people’s lives. The current preoccupation with watching David Blaine, half-naked and self-imprisoned in a giant perspex box like a real-life prisoner of reality TV would suggest that curiosity bordering on prurience has become the dominant theme of our times. What began in the dawn of TV as soap opera has been transformed, as the prescient film The Truman Show suggested it would be, into a global village obsessed with the minutiae of how real-life people behave. EM Forster observed that on marriage, a glass curtain descends between a couple and the rest of the world; we all wonder how other people, and particularly other couples, behave behind it. Pretending to be them, or watching someone else do that by proxy, is probably as close as any of us will come to satisfying this curiosity.

The concept of stepping into someone else’s life and pretending to be them is a very ancient one. Long before films such as Trading Places and Face/Off, and long before David’s Lodge’s comic masterpiece Changing Places, Mark Twain imagined what would happen if a poor boy was mistaken for a rich one in The Prince and the Pauper. Mozart’s best-loved opera, The Marriage of Figaro, has its Countess pretending to be her maid, in order to expose her philandering husband; Shakespeare’s All’s Well that Ends Well, and numerous stories in The Arabian Nights also feature such exchanges of identity. All of these are enjoyable fantasies with a thumping moral message about loving your neighbour as yourself – the foundation of a good and kindly civilisation. What is different about the TV series is that they offer real people, acting more or less spontaneously in situations we all recognise and often relate to. Like fairy-tales they offer no prescription as to how we should lead our lives, but instead cause us to ponder the things we all argue about and that matter to us. How do we, in an increasingly fragmented world in which the traditional roles of bread-winner and house-keeper have been shared or reversed, manage raising a family? What are other people, and by extension ourselves, doing better or worse? How are chores divided, meals cooked and the work-life balance we all fret about managed by them. Is it really true that poor people have no idea how to cook and nourish their children – or is it the case, as in the Portillo life-swap, that actually it’s the rich ones who haven’t a clue? Do formal good manners matter at table, or it is more important to convey that reading is fun? Where Neighbours from Hell invited us to see its families as grotesque and ridiculous, and where Changing Rooms presents us with style-free victims, what emerges is something more humane than is usual on TV.

Channel 4’s Wife-Swap series, despite it’s tacky-sounding title, has had an equally interesting effect on the nation. The programme that showed a nice black woman, Sonia, galvanising an appallingly slobbish white family probably did more for real-life race relations than Trevor Philips. Her energy in cleaning the house, disciplining the white family’s rude and racist children, and getting her temporary “husband” down to the gym was awe-inspiring. The private effects of appearing in the programme was equally benign, for we learnt that while the cameras were off the couple, Sonia’s boyfriend Lance, horrified by life with the dismal Dee, proposed marriage to her.

Another couple, Barry and Michelle, were jolted out of a marriage in which Barry’s belief that “the best women to go out with are really ugly ones because they are so grateful to you they do all the chores.” When his wife returned an emancipated woman, Barry left; only to come crawling back after four moths of searching for someone else to bring him his porridge and a drink in the mornings. Both lovely Lance and beastly Barry had been forced to re-evaluate the woman in their lives, and recognise that she was worth more respect than they had previously thought. Equally, the almost fairy-tale contrast between two brothers, rich, selfish Jason and poor, loving Dave was riveting as their wives coped with each other’s lives. The most moving aspect of all was seeing how the children suffer from their parents’ unthinking assumptions about and demands on each other. Couples watching their criticisms, discoveries and appraisals may also have had cause to renegotiate their own compacts with their families. Everybody recognises aspects of themselves in these programmes; just as the couples in last weeks programme about a junk-food husband and a vegan wife caused both partners to reassess their behviour, and make fundamental changes so viewers are given something original and potentially life-changing. Instead of the superficial life-style formats such as House Doctor and What Not to Wear, which sneer at the wrong choices made by real people, something suspiciously like real ethical questions are posed about the way we live now.

Once upon a time, this was precisely what novels used to do. Dickens, Trollope, Tolstoy, Balzac and Mrs. Gaskell all brought news of other social classes and other relationships to their readers. They posed moral and social questions about the marriage contract and the social contract through intimate, if fictional, domestic scenes and stories. Their characters, too, changed social position: upwards in the case of Pip in Great Expectations and Balzac’s Lost Illusions, or downwards in Jane Eyre and Anna Karenina. We still, clearly, have a hunger for their kind of realism – for the novelty and the dilemmas it kindles when struck against our own sense of propriety, social conformity and transgression. The pity is that, now, where writers such as Monica Ali and Zadie Smith are praised for giving white middle-class readers the same kind of insight into a different culture, they do not pose the other half of the question. What do we owe each other – and society? The recent Life Swap concerning an “aspirational” couple, the Sprys of Exeter, with the perennially unemployed Bardsleys of Rochdale - 8 children, an income of £37,000 a year in state benefits - excited a frenzy on Kilroy and in the tabloids. It touched on the deep indignation and fear of the hard-working that there are families of scroungers living the life of, well, the Bardsleys, with their wide-screen TV and home decorated on tax-payers’ money.

Where contrasts are as crude as this, there is heat not light. As David Blaine has found, people are as likely to throw tomatoes at someone on public display as they are to cheer and encourage. Most of us exist half-way between the state of Prince and Pauper; we struggle to see ourselves, and see what our children really want from us, although it may be quite clear to onlookers. What has been lost, and what is being regained through these extraordinary series, is a dialogue between people who should be close, and often aren’t – the kind of dialogue that encourages thoughtfulness, kindness, politeness and mutual support. When people everywhere believed that every human action was noted by God, they were coerced into good behaviour. When that belief was exploded in the 2oth century, people felt free to behave as badly as they felt like, with no check or consciousness of how they might appear to others. Now there is the eye of the camera, recording our every crime in public or private, and displaying it to the rest of the world. Whether it is vengeful or charitable is going to be up to us.

Amanda Craig’s new novel, Love in Idleness, is published by Litte,Brown £12.99